Lifi network and associated method

ABSTRACT

The present disclosure is directed to examples of a light fixture. In one embodiment, the light fixture includes a light source to emit a light, a photo detector to detect an incoming light, a transceiver to receive incoming data and transmit data, a modulator/demodulator to modulate the light with the data and to demodulate the incoming light with the incoming data, and a processor communicatively coupled to the light source, the photo detector, the transceiver, and the modulator/demodulator, wherein the processor is to control the modulator/demodulator to modulate the light at a transmission frequency to transmit the data via the light.

CROSS REFERENCE TO RELATED APPLICATIONS

This application claims priority under 35 U.S.C. § 119(e) to U.S.provisional patent application Ser. No. 62/808,380, filed on Feb. 21,2019, which is hereby incorporated by reference in its entirety.

BACKGROUND

Industry today relies on the transmission of data. Data is continuouslytransmitted for monitoring, automation control, and the like. Typically,data can be transmitted over wired and wireless networks that aredeployed for transmitting data. For example, fiber optics networks andwireless networks with routers and gateways may be deployed to build acommunication network. The cost to deploy these networks can be veryexpensive.

SUMMARY

In one embodiment, the present disclosure provides a light fixture. Inone embodiment, the light fixture comprises a light source to emit alight, a photo detector to detect an incoming light, a transceiver toreceive incoming data and transmit data, a modulator/demodulator tomodulate the light with the data and to demodulate the incoming lightwith the incoming data, and a processor communicatively coupled to thelight source, the photo detector, the transceiver, and themodulator/demodulator, wherein the processor is to control themodulator/demodulator to modulate the light at a transmission frequencyto transmit the data via the light.

In one embodiment, the present disclosure provides a lighting systemdata network. In one embodiment, the lighting system data networkcomprises a data source to transmit data, a first light fixture toreceive the data and to transmit a modulated light signal with the data,a second light fixture to receive the modulated light signal with thedata, to demodulate the modulated light signal with the data, and totransmit the data to a data destination, and a data destination toreceive the data.

In one embodiment, the present disclosure provides a method fortransporting data across a lighting system data network. In oneembodiment, the method comprises receiving, via a processor of a lightfixture, data, modulating, by the processor, a light emitted by thelight fixture to carry the data, and transmitting, by the processor, thelight that is modulated to carry the data to a second light fixture.

BRIEF DESCRIPTION OF THE DRAWINGS

So that the manner in which the above recited features of the presentdisclosure can be understood in detail, a more particular description ofthe disclosure, may be had by reference to embodiments, some of whichare illustrated in the appended drawings. It is to be noted, however,that the appended drawings illustrate only typical embodiments of thisdisclosure and are therefore not to be considered limiting of its scope,for the disclosure may admit to other equally effective embodiments.

FIG. 1 depicts a block diagram of one embodiment of a light fixture ofthe present disclosure;

FIG. 2 depicts a block diagram of one embodiment of an example of alighting system data network that includes the light fixtures of thepresent disclosure;

FIG. 3 depicts a block diagram of one embodiment of an example of alighting system data network that uses reflected light to communicate ofthe present disclosure;

FIG. 4 depicts a block diagram of an example lighting system datanetwork of the present disclosure;

FIG. 5 depicts a block diagram of an example lighting system datanetwork organized in a tree structure of the present disclosure;

FIG. 6 depicts a flow diagram of an example method for transporting dataacross a lighting system data network of the present disclosure.

DETAILED DESCRIPTION

The present disclosure provides a lighting system data network that cantransmit data across multiple lighting fixtures. As noted above,industry today relies on the transmission of data. Data is continuouslytransmitted for monitoring, automation control, and the like. Typically,data can be transmitted over wired and wireless networks that aredeployed for transmitting data. For example, fiber optics networks andwireless networks with routers and gateways may be deployed to build acommunication network. The cost to deploy these networks can be veryexpensive.

However, all facilities use lights to illuminate the facilities. Thus,using the lights inside of a facility to transport data may reduce theoverall costs for implementing a separate communication network totransmit the data.

Examples of the present disclosure build upon the existing technologyknown as visible light communications (VLC) and LiFi, both of which uselight to transmit information. The present disclosure extends theprevious technologies by fitting the lighting fixture with both atransmitter and receiver such that data may be sent to and from fixtureto fixture. Notably, no other previous VLC systems uses two or morelighting fixtures for data transmission using light.

In some embodiments, the light used may be visible, infrared, orultraviolet. The light may be modulated at various frequencies totransmit the data. In some embodiments, a lighting fixture and a laptopdongle device enabling the access-point to the network over the lightingsystem data network (also referred to herein as the LiFi network) may bedeployed.

Thus, the present disclosure can use lighting fixtures in a location totransmit data. Using the lighting fixtures can significantly reduce thecost for data networks in a facility or location compared to deploying aseparate data network.

FIG. 1 illustrates an example light fixture 100 of the presentdisclosure. Multiple instances of the light fixture 100 may be deployedas part of a lighting system data network illustrated in FIGS. 2-5 anddiscussed in further details below.

In one embodiment, the light fixture 100 may include a processor 102, amodulator/demodulator 104, a transceiver 106, a photodetector 108, and alight source 110. The processor 102 may be communicatively coupled tothe modulator/demodulator 104, the transceiver 106, the photodetector108, and the light source 110 to control operation of themodulator/demodulator 104, the transceiver 106, the photodetector 108,and the light source 110.

In one embodiment, the light source 110 may include at least one lightemitting diode (LED). The light source 110 may include an array of LEDsthat can be used to illuminate a location and be modulated to transmitdata. In one embodiment, the light emitted by the light source may havea wavelength between approximately 380 nanometers (nm) to 780 nm. Itshould be noted that the term light and light signal may be usedinterchangeably herein.

In one embodiment, the light source 110 may include two different LEDs.For example, an array of a first type of LED may be used to emit lightat wavelengths to illuminate a location. An array of a second type ofLED may be used to carry data. The light or light signal emitted by thesecond type of LED may be modulated, as discussed in further detailsbelow, to carry the data.

In one embodiment, the photodetector 108 may detect incoming lightsignals. The detected incoming light signals may be provided to theprocessor 102 for processing. For example, the incoming light signalsmay be demodulated by the modulator/demodulator 104 to obtain data thatis carried by the incoming light signals.

In one embodiment, the modulator/demodulator 104 may modulate a lightemitted by the light source 110 to carry data. The modulator/demodulator104 may also demodulate incoming light detected by the photodetector 108to obtain data carried by the incoming light, as noted above. In oneembodiment, the modulator/demodulator 104 may apply a broadbandmodulation to the light signal. For example, the data may be transmittedover a wide bandwidth of frequencies at a lower overall power.

In one embodiment, the modulator/demodulator 104 may modulate the lightthe signal using a spread spectrum modulation encoding. For example, thedata may be broken up into different frequencies and then aligned by amodulator/demodulator 104 of a receiving light fixture 100 to retrievethe data from the light signal. The spread spectrum modulation encodingmay offer a secure transmission of the data with low interference. Thedata may be carried by the light signals over a wide range offrequencies having a relatively low power density compared to anarrowband signal. Different types of spread spectrum modulationencoding may include frequency hopped spread spectrum (FHSS), directsequence spread spectrum (DSSS), and the like. The DSSS may transmitdata with pseudo-random number sequences.

In one embodiment, the spread spectrum encoding contains inherent noisetolerance which may allow proper signal reception in an area withmultiple fixtures transmitting information simultaneously. Due to thepotential use of reflected light that the lighting network data network(e.g., illustrated in FIG. 3 and discussed below) of the presentdisclosure may use, this ability may be used to decode a clear signalfrom a noisy environment.

In one embodiment, the light may be modulated by turning the lightsource 110 on and off. The light source 110 may be turned on and off ata frequency that is fast enough to be unnoticeable by a human eye, butcan be detected by the photodetector 108 and processed by the processor102 and the modulator/demodulator 104.

In one embodiment, the light may be modulated by changing a brightnessof the light source 110. For example, the brightness of the light source110 may be increased and decreased at a desired frequency. For example,the brightness may be varied with 16 or 24 bit resolution and can conveymore information than turning the light source 110 on and off.

In one embodiment, the light may be modulated at a frequency between 10kilohertz to 770 terahertz. In one embodiment, the light may bemodulated at a frequency between 420 terahertz to 770 terahertz. In oneembodiment, the light may be modulated at a frequency between 10kilohertz to 1 terahertz.

In one embodiment, the transceiver 106 may be a combination of atransmitter and transceiver. The transceiver 106 may be a wirelesstransceiver that can communicate via wireless signals (e.g., radiofrequency (RF) signals). The transceiver 106 may receive data from adata source. The data may then be processed by the processor 102 onto amodulated light signal. The transceiver 106 may transmit data that isdemodulated from a light signal to a data destination.

In one embodiment, the light fixture 100 may also include an optionalband pass filter (not shown). The band pass filter may filter outundesired light wavelengths and/or frequencies. The band pass filter mayprevent light pollution from other light sources in a location that cancause false signals from being processed by the light fixture 100.

FIG. 2 illustrates an example of a light system data network 200 of thepresent disclosure. The light system data network 200 may include aplurality of light fixtures 100. The example in FIG. 2 illustrates twolight fixtures 100 ₁ and 100 ₂. However, it should be noted that anynumber of light fixtures may be deployed.

In one embodiment, the two light fixtures 100 ₁ and 100 ₂ maycommunicate bi-directionally. For example, the light fixture 100 ₁ maytransmit modulated light signals that carry data, as described above, tothe light fixture 100 ₂, and vice versa. The light fixture 100 ₂ maymeasure the incoming modulated light using the photodetector 108. As aresult, digital information may be transmitted from the light fixture100 ₁ to the light fixture 100 ₂. This communication technique may bereferred to as LiFi.

As noted above, the present disclosure leverages the light fixtures 100of the present disclosure to provide the LiFi link between two or morelight fixtures 100. In contrast, current LiFi communication networks arelimited between one light fixture and an access point. In other words,current LiFi communication networks do not have a light fixture that cancommunicate with other light fixtures.

In one embodiment, the data may be retrieved by the light fixture 100 ₂from demodulating the modulated light received from the light fixture100 ₁. The data may then be transmitted to a computing device 202. Thecomputing device 202 may be a laptop computer, a desktop computer, atablet computer, and the like, that includes a dongle 204 that iswirelessly connected to a wide area network (WAN) 206. The WAN 206 maybe an Internet protocol (IP) network. The data may then be transmittedby the computing device 202 to any desired data destination that isconnected to the WAN 206.

FIG. 3 illustrates a block diagram of an example light system datanetwork 300 that uses reflected light to communicate of the presentdisclosure. The vast majority of light that enters the human eye reachesthat point via one or more reflections off of surrounding surfaces.Illumination we see on the surfaces of rooms, buildings, and streets isthe result of reflected light entering the eye. This principle can beused to extend conventional LiFi data transmission to allow the creationof continuous tree or mesh networks, useful in forming networks forhome, commercial, and industrial purposes.

In one embodiment, the light system data network 300 may include areflector 302. The reflector 302 may be a fixed mirror, a reflector, ametalized reflector, and the like. Although a single reflector 302 isillustrated in FIG. 3 for ease of explanation, it should be noted thatany number of reflectors 302 may be deployed in a location. In addition,the reflectors 302 may all be the same type of reflector or may bedifferent types of reflectors.

In one embodiment, using reflected light may allow a communication linkto be formed between two light fixtures 100 ₁ and 100 ₂ without having alight signal 304 travel directly from the light fixture 100 ₁ to thelight fixture 100 ₂. Rather, the light signal 304 may arrive via areflected path. In other words, the two lighting fixtures 100 ₁ and 100₂ may not be arranged or positioned such that there is a direct line ofsight. Said another way, an obstruction or structure 306 may be locatedbetween the two lighting fixtures, and the light signal 304 may bereflected by the reflector 302 to allow the two light fixtures 100 ₁ and100 ₂ to still communicate.

In one embodiment, the light sources 110 of the light fixtures 100 ₁ and100 ₂ may be adjusted or calibrated to emit the light signal 304 in adirection towards the reflector 302. The LEDs of the light sources 110may be moved to emit the light signal 304 towards the reflector 302,reflectors or optics (not shown) within the light fixtures 100 ₁ and 100₂ may be used, or the light fixtures 100 ₁ and 100 ₂ may be installed ormounted in such a way to direct the light signal 304 towards thereflector 302.

In one embodiment, the reflector 302 may be coupled to or mounted on agimbal or movable mount 308. The mount 308 may be coupled to a motor310. The motor may move the mount 308 under the control of a controller(not shown) to reflect the light signal 304. For example, the reflector302 may be angled to allow the light signal 304 to be reflected towardsthe light fixture 100 ₂. The reflector 302 may then be moved to anglethe light signal 304 to another light fixture 100 that may be locatednearby.

The ability to reflect the light signal 304 may be valuable as thereflected path is far easier to implement and allows the implementationof a true LiFi fixture—one in which the primary LED light that providesillumination is also the light that is used for data transport. Theamount of light produced by one conventional LED fixture may be largeenough to detect via a reflected path at considerably remote distances.

FIG. 4 illustrates a block diagram of one embodiment of an example lightsystem data network 400 of the present disclosure. In one embodiment,the light system data network 400 may be a backhaul network fornon-lighting-centric data. The data transmitted by a data source 402 andreceived by the data destination 404 may include non-lighting data andmay be transmitted across the light fixtures 100 ₁ to 100 _(n).

For example, as discussed above, data may be transmitted from the datasource 402 to an adjacent or nearby light fixture 100 ₁. The lightfixture 100 ₁ may receive the data and modulate a light signal to carrythe data to a data destination 404. The data source 402 may be amachine, a sensor, a security camera, a piece of equipment in a factory,a computing device in an office building, and the like. The data source402 may transmit operation data or control signal data. The datadestination 404 may be a remotely located server, another sensor,another computing device at a different office building, anothermachine, and the like

In one embodiment, the light signal modulated by the light fixture 100 ₁may be passed along subsequent light fixtures 100 ₂-100 _(g). The lastlight fixture 100 _(g) may demodulate the light signal to obtain thedata carried by the modulated light signal. The light fixture 100 _(g)may then transmit the data to the data destination (e.g., over the WANillustrated in FIG. 2, and discussed above). The function of thelighting system data network 400 as a data transport network may havemany possible implementations as an “available everywhere” network whichcan be tapped to send or to receive data from a remote or centralizedlocation.

In one embodiment, the data source 402 may include hardware that may beLiFi enabled. For example, the data source 402 may also include a lightsource, a modulator/demodulator, and a photodetector to transmit andreceive modulated light signals that carry data generated by the datasource 402. The data source 402 may directly communicate with the lightfixture 100 ₁ such that the light fixture 100 ₁ may simply pass themodulated light signal. In other words, the light fixture 100 ₁ may nothave to perform the modulation of the light signal.

FIG. 5 illustrates a block diagram of an example lighting system datanetwork 500 that is organized in a tree structure of the presentdisclosure. The light fixtures 100 can be organized in a variety ofdifferent ways. One example is a tree structure as illustrated in FIG.5.

The tree structure may lead back to a central network coordinator or berealized in a mesh network configuration. The flexibility of the way thelight fixtures 100 can be arranged may be useful when forming a networkin a difficult environment.

In one embodiment, the lighting system data network 500 may include aplurality of light fixtures 100 ₁ to 100 _(m). A subset of lightfixtures 100 ₄-100 _(m) may form a backbone or central line of thelighting system data network 500. For example, the light fixtures 100₄-100 _(m) may represent parent nodes of a tree.

Other light fixtures (e.g., light fixtures 100 ₁, 100 ₂, 100 ₃, 100 ₈,100 ₉, 100 ₁₀, and 100 ₁₁) may branch off from the light fixtures 100 ₄to 100 _(m) in the central line. The other light fixtures 100 ₁, 100 ₂,100 ₃, 100 ₈, 100 ₉, 100 ₁₀, and 100 ₁₁ may represent child nodes of thetree.

In one embodiment, one of the light fixtures (e.g., the last lightfixture 100 _(m)) may serve as a central network coordinator. The lightfixture 100 _(m) may communicate with a gateway device 502. All of thedata carried by various different modulated light signals may bedemodulated by the light fixture 100 _(m). The data from the differentmodulated light signals may then be transmitted over a communicationsnetwork or WAN via the gateway device 502.

In one embodiment, the gateway device 502 may include a LiFi transceiverand may transmit and receive light signals. The gateway device 502 mayinclude a connection interface to the WAN. The connection interface maybe an Ethernet connection or a wireless connection.

This example light system data network 500 illustrated in FIG. 5 mayhave several advantages when compared to conventional networkingtechnology. First, the network 500 may be wireless. Second, the network500 may not be constrained by regulations as is found in the radiofrequency spectrum. Third, the network 500 may offer the ability forvery high speed communications. The arrangement of the light system datanetwork 500 may be formed similar to radio-based tree or mesh networksuch as is used in ZigBee networks. However, unlike these other types ofnetworks, the network 500 of the present disclosure may be built onLiFi-based communication, as opposed to radio-based communication.Another benefit of using the lighting fixtures 100 in the network 500 isthat in a typical installation, the network 500 may have good networkcoverage because the light fixtures 100 are naturally spread throughouta facility.

FIG. 6 illustrates a flowchart of one embodiment of a method 600 fortransporting data across a lighting system data network of the presentdisclosure. In one embodiment, the method 600 may be executed by thelighting fixture 100.

The method 600 begins at block 602. At block 604, the method 600receives data. For example, the data may be non-light related data. Thedata may be received from a data source such as a machine, a piece ofequipment, a sensor, and the like.

At block 606, the method 600 modulates a light emitted by the lightfixture to carry the data. In one embodiment, the light may be modulatedby turning a light source in the light fixture on and off. In anotherembodiment, the light may be modulated by changing a brightness level ofthe light source in the light fixture. For example, the brightness maybe varied with 16 or 24 bit resolution and can convey more informationthan turning the light source on and off.

In one embodiment, the light fixture may have a single set of LEDs thatis used for illumination and for modulation to carry the data. Inanother example, the light fixture may include a first set of LEDsdedicated to illumination and a second set of LEDs dedicated to beingmodulated to carry the data.

In one embodiment, the light source may emit light at a wavelengthbetween approximately 380 nm to 780 nm. In one embodiment, the light maybe modulated at a frequency between 10 kilohertz to 770 terahertz. Inone embodiment, the light may be modulated at a frequency between 420terahertz to 770 terahertz. In one embodiment, the light may bemodulated at a frequency between 10 kilohertz to 1 terahertz.

In one embodiment, the light may be modulated via a broadband modulator.The light may also be modulated using spread spectrum modulationencoding. For example, FHSS or DSSS can be used modulate the light.

At block 608, the method 600 transmits the light that is modulated tocarry the data to a second light fixture. For example, the modulatedlight that carries the data may be transmitted to the second lightfixture. The second light fixture may detect the modulated light signaland either pass the signal to another light fixture or demodulate themodulated light signal to obtain the data. The data may then betransmitted to a data destination (e.g., a remote server, a remotedatabase, a remote sensor, a remote computing device, and the like). Atblock 610, the method 600 ends.

It should be noted that steps, operations, or blocks in FIG. 6 thatrecite a determining operation, or involve a decision, do notnecessarily require that both branches of the determining operation bepracticed. In other words, one of the branches of the determiningoperation can be deemed as an optional step. Furthermore, operations,steps, or blocks of the above described methods can be combined,separated, and/or performed in a different order from that describedabove, without departing from the example embodiments of the presentdisclosure.

While various embodiments have been described above, it should beunderstood that they have been presented by way of example only, and notlimitation. Thus, the breadth and scope of a preferred embodiment shouldnot be limited by any of the above-described exemplary embodiments, butshould be defined only in accordance with the following claims and theirequivalents.

What is claimed is:
 1. A light fixture, comprising: a light source toemit a light; a photo detector to detect an incoming light; atransceiver to receive incoming data and transmit data; amodulator/demodulator to modulate the light with the data and todemodulate the incoming light with the incoming data; and a processorcommunicatively coupled to the light source, the photo detector, thetransceiver, and the modulator/demodulator, wherein the processor is tocontrol the modulator/demodulator to modulate the light at atransmission frequency to transmit the data via the light.
 2. The lightfixture of claim 1, wherein the processor is to control themodulator/demodulator to demodulate the incoming light at a receptionfrequency to obtain the incoming data.
 3. The light fixture of claim 1,wherein the processor is to module the light via spread spectrummodulation encoding.
 4. The light fixture of claim 1, wherein the lightis emitted at a wavelength between 380 nanometers (nm) to 780 nm.
 5. Thelight fixture of claim 1, wherein the light is modulated by turning thelight source on and off.
 6. The light fixture of claim 1, wherein thelight is modulated by changing a brightness of the light source.
 7. Thelight fixture of claim 1, wherein the light is modulated at a frequencybetween 430 terahertz to 770 terahertz.
 8. The light fixture of claim 1,wherein the light is modulated at a frequency between 1 kilohertz to 1terahertz.
 9. The light fixture of claim 1, wherein the light sourcecomprises: a first array of light emitting diodes (LEDs) to emit lightat a first wavelength to illuminate a location; and a second array ofLEDs to emit light at a second wavelength to transmit the data.
 10. Alighting system data network, comprising: a data source to transmitdata; a first light fixture to receive the data and to transmit amodulated light signal with the data; a second light fixture to receivethe modulated light signal with the data, to demodulate the modulatedlight signal with the data, and to transmit the data to a datadestination; and a data destination to receive the data.
 11. Thelighting system data network of claim 10, further comprising: a gatewayto receive the data from the second light fixture and to transmit thedata to the data destination.
 12. The lighting system data network ofclaim 10, further comprising: a computing device to receive the datafrom the second light fixture and to transmit the data to the datadestination over a wide area network.
 13. The lighting system datanetwork of claim 10, further comprising: at least one reflector toreflect the modulated light signal from the first light fixture to thesecond light fixture.
 14. The lighting system data network of claim 10,wherein the modulated light signal with the data is modulated at afrequency between 430 terahertz to 770 terahertz.
 15. The lightingsystem data network of claim 10, wherein the light is modulated at afrequency between 1 kilohertz to 1 terahertz.
 16. A method, comprising:receiving, via a processor of a light fixture, data; modulating, by theprocessor, a light emitted by the light fixture to carry the data; andtransmitting, by the processor, the light that is modulated to carry thedata to a second light fixture.
 17. The method of claim 16, wherein themodulating is performed by turning a light source of the light fixtureon and off or changing a brightness of the light source.
 18. The methodof 16, wherein the light is modulated at a frequency between 430terahertz to 770 terahertz.
 19. The method of claim 16, wherein thelight is modulated at a frequency between 1 kilohertz to 1 terahertz.20. The method of claim 16, wherein the light is modulated using aspread spectrum modulation encoding.